Ceramic Terms and Vocabulary


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Bag wall –  firebrick structure which prevents intense heat from striking the ware

Bat – A disc of wood, plaster or plastic used on the wheel head

Beaker- a tall cup

Blisters – bubbles formed in the body or glaze due to rapid gas release

Bisque – ware which has been fired once and is unglazed

Bottle Kiln – type of Europen updraught kiln in the shape of a bottle

Calipers – tool for measuring diameter of pots, useful for making lids

Celadon – traditionally a type of greenish Asian glazes

Chatter – decorative technique using a tool to create marks on a pot while it spins on the wheel

Chun Glaze – a traditional sung dynasty opalescent Chinese glaze

Coiling – an ancient way of making pots with coils or ropes of clay to build the walls

Collaring – Reducing the size of an opening by compressing the clay while it spins on the wheel

Combing- a decoration technique that uses a comb to draw lines on the surface of the pot

Crackle – Decorative craze lines in the glaze, looks like netting (not food safe)

Crazing – Formation of a network of cracks in the glaze (not food safe) a glaze fault

Crystalline – Crystal formations on the surface of the pot from certain glazes

Damper – Device for adjusting or closing the opening from the kiln to the chimney

De-air – To remove the air from clay via a machine called a pug-mill

Deflocculate – To disperse the particles in slip so less water is required for fluidity

Dehydration – loss of water from clay during firing

Devitrify – to recrystallize on cooling

Dipping – immersing pots in glaze or slip

Distortion – happens when pots dry to rapidly or unevenly

Downdraught(downdraft)- type of kiln in which the flames travel down over the ware

Dunt – to break from strains during cooling, can be caused by cool air entering the kiln

Earthenware – Low fired pottery, is porous and permeable even when fired

Engobe – another name for slip

Extrude – process of making shapes by forcing clay though tubes with dies

Fettle – to smooth the surface of leather hard clay

Fiaence – glazed earthenware

Firebox – where the fuel is fed into a kiln

Firing – The burning or running of a kiln

Fit – the adjustment of a glaze to the clay body

Flashing – the impingement of flame on a pot during the firing

Flocculate – to thicken

Flux – a substance which promotes or causes melting

Frit – A material used in glazes, consisting of fired glass that is ground to powder

Fuse – to melt

Glassification – turning or melting into glass

Greenware – unfired pottery

Grog – fired clay that has been ground into granules

Gum Arabic – used as a siccative with overglaze enamel

Hare’s Fur – a streaked brown glaze, originating in Japan

Heat work – a form of physical energy

Kiln- used to fire pottery, multiple of types, electric, wood, gas

Kiln post – made from a refractory material, to hold up kiln shelves

Kiln Shelves – refractory shelves that hold ware in the kiln

Kiln Stilt- small posts that you can fire glazed ware on so it won’t touch the shelf

Kiln Wash –  a refectory mixture, painted on kiln shelves to prevent sticking

Leather-hard – clay dried to where it is stiff yet wet enough to trim or join with slip

Lug – a type of knob used as a handle

Luster – metallic overglaze applied to glazed ware and fired at low temps

Majolica – a type of Italian tin enameled pottery with colorful surface painting

Master Mold – a plaster mold that repeated copies can be made from

Matt Glazes – type of glaze with a dull surface

Mature – Fired to a tight, hard, serviceable structure

Mishima – inlaid slip decoration technique, Japanese in origin

Oil Spots – lustrous metallic spots on dark iron glazes

Open clays – porous or sandy textured clay with added fillers or grog

Overglaze – enamel painting on a glazed surface which is fired also referred to as china painting

Oxide – any element combined with oxygen

Oxidation – firing of a kiln with an oxygen rich atmosphere

Porcelain – a white, vitrified, translucent clay body

Pug Mill – a machine that mixes, de-airs and extrudes clay

Pyrometer – a device for measuring temperature in a kiln

Pyro cones – cones that gauge heat in a kiln which bend and melt at certain temperatures

Raku – a type of glaze and firing method based on the Japanese tea ceremony firing and wares

Raw Glaze- glaze that can be applied to unfired ware

Reduction – firing with a reduced oxidation atmosphere in the kiln

Refractory- resistant to heat

Rib – a tool used for smoothing the surface of a pot during throwing, compressing or finishing

Sagger – a fire clay box which protects ware from flame during firing

Salt Glaze – glazing by the vapors from salt in the kiln

Sgraffito –decorative technique where you scratch through slip to reveal the clay underneath

Shards – broken pieces of pottery

Shrinkage – the contracting of clay during drying in firing, can be up to 25% in some clays

Short Clay – nonplastic clay body with poor working properties

Slake – to moisten clay with water

Slip – a fluid suspension of clay and other materials in water, also referred to as an engobe

Slip Trailing – a decorative method using slip to draw on the surface

Slip Casting – a method of forming pots by pouring slip into plaster molds

Slurry – a mixture of clay and water

Soak – to hold a kiln at one temperature for a period of time

Soda Firing- atmospheric firing where soda is introduced into the kiln

Soluble – dissolved in water

Sprig- a relief decoration added to the clay surface, sprigs are usually formed in a mold

Stack or load- to set a kiln with pottery

Stoneware – pottery fired to a relatively high temp at which the body vitrifies

Terra Sigillata –  refined slip used to color and seal a porous clay body

Throw- to make pottery on a pottery wheel

Tooth –roughness of a clay, grain structure

Viscosity – the relative resistance of a liquid to movement

Wad – bits of clay to hold down pots for trimming or for setting pots on in atmospheric firing

Wax Resist – when applied to the surface it prevents the adhesion of glazes and slips

Wedge – to remove air from clay by kneading with your hands